From a391990f2a52695b3c56afedaea5ffb80581f1e4 Mon Sep 17 00:00:00 2001
From: Andrei Kortunov <andrei.kortunov@yandex.ru>
Date: Mon, 20 Nov 2017 21:30:46 +0400
Subject: [PATCH] Provide multibyte toLower() and single chars comparator

---
 apps/openmw/mwgui/journalviewmodel.cpp | 46 ++++++++++++++++----------
 components/misc/stringops.hpp          | 30 +++++++++++++++++
 2 files changed, 58 insertions(+), 18 deletions(-)

diff --git a/apps/openmw/mwgui/journalviewmodel.cpp b/apps/openmw/mwgui/journalviewmodel.cpp
index 02103280b..33935f040 100644
--- a/apps/openmw/mwgui/journalviewmodel.cpp
+++ b/apps/openmw/mwgui/journalviewmodel.cpp
@@ -311,29 +311,39 @@ struct JournalViewModelImpl : JournalViewModel
 
         for (MWBase::Journal::TTopicIter i = journal->topicBegin (); i != journal->topicEnd (); ++i)
         {
-            if (i->first.length() < 2)
-                continue;
-
             unsigned char byte1 = i->first[0];
-            unsigned char byte2 = i->first[1];
+            // First, check for two-byte UTF-8 symbols, e.g. Cyrillic ones
+            // TODO: check which language journal index is using
+            if ((byte1 == 0xd0 || byte1 == 0xd1) && i->first.length() >= 2)
+            {
+                unsigned char byte2 = i->first[1];
 
-            // Upper case
-            if (byte1 == 0xd0 && byte2 >= 0xb0 && byte2 < 0xc0)
-                byte2 -= 32;
+                std::pair<unsigned char, unsigned char> symbol = Misc::StringUtils::toLower(byte1, byte2);
 
-            if (byte1 == 0xd1 && byte2 >= 0x80 && byte2 < 0x90)
-            {
-                byte1 -= 1;
-                byte2 += 32;
-            }
+                // CYRILLIC LETTER A - CYRILLIC LETTER PE
+                // index from 1 to 16
+                if (symbol.first == 0xd0 && symbol.second >= (0xaf + index) && symbol.second < (0xbf + index) && symbol.second == (0xaf + index))
+                {
+                    visitor (i->second.getName());
+                    continue;
+                }
 
-            // CYRILLIC CAPITAL A is a 0xd090 in UTF-8
-            // so we can use 0xd08f + index
-            // (index is a position of letter in alphabet, begins from 1)
-            if (byte1 != 0xd0 || byte2 != 0x8f + index)
-                continue;
+                // CYRILLIC LETTERL R - CYRILLIC LETTER YA
+                // index from 17 to 32
+                if (symbol.first == 0xd1 && symbol.second >= (0x6f + index) && symbol.second < (0x7f + index) && symbol.second == (0x6f + index))
+                {
+                    visitor (i->second.getName());
+                    continue;
+                }
+            }
+            else
+            {
+                // Otherwise check for regular Latin symbols, 0x61 = 'a'
+                if (i->first [0] != 0x60 + index)
+                    continue;
 
-            visitor (i->second.getName());
+                visitor (i->second.getName());
+            }
         }
     }
 
diff --git a/components/misc/stringops.hpp b/components/misc/stringops.hpp
index 9acd81710..97865a44c 100644
--- a/components/misc/stringops.hpp
+++ b/components/misc/stringops.hpp
@@ -55,6 +55,36 @@ public:
         };
     }
 
+    static std::pair<char, char> toLower(unsigned char byte1, unsigned char byte2)
+    {
+        std::pair<unsigned char, unsigned char> symbol = std::make_pair(byte1, byte2);
+        // CYRILLIC CAPITAL IO
+        if (symbol.first == 0xd0 && symbol.second == 0x01)
+        {
+            symbol.first++;
+            symbol.second = 0x91;
+        }
+        // CYRILLIC CAPITAL A - CYRILLIC CAPITAL PE
+        else if (symbol.first == 0xd0 && symbol.second >= 0x90 && symbol.second < 0xa0)
+        {
+            symbol.second += 0x20;
+        }
+        // CYRILLIC CAPITAL R - CYRILLIC CAPITAL YA
+        else if (symbol.first == 0xd0 && symbol.second >= 0xa0 && symbol.second < 0xb0)
+        {
+            symbol.first++;
+            symbol.second -= 0x20;
+        }
+        // Other symbols
+        else
+        {
+            symbol.first = toLower(symbol.first);
+            symbol.second = toLower(symbol.second);
+        }
+
+        return symbol;
+    }
+
     static bool ciLess(const std::string &x, const std::string &y) {
         return std::lexicographical_compare(x.begin(), x.end(), y.begin(), y.end(), ci());
     }